This chapter introduces the production of the positive pions which are needed for the experiment. A general description of the accelerator which delivers the particle beam is presented. The development runs, intended to optimize of the beam channel for pure pion beam and minimal pion stopping volume are also discussed in conjuction with the results of these runs.
The accelerator facility at Paul Scherrer Institute (PSI) offers a large variety of intense particle beams and irradiation possibilities. The facility comprises three cyclotrons known as Injector 1, Injector 2 and the Ring. For the purposes of the pion beta decay experiment, Injector 2 and the Ring are relevant. Injector 2 delivers 72 MeV protons to the Ring which in turn accelerates them to 590 MeV. These protons are transported to two graphite production targets of length (Target M) and (Target E) in the direction of the proton beam.
Table: Properties of the PSI Ring Accelerator.
At Target E, five secondary beams are
extracted, one of which is the beam used by various
experiments including pion beta decay experiment mentioned in the previous
chapter. Some properties of the Ring are summarized in